Labour party leader Ed Miliband arrives at Kings Cross Station in London

Labour has raced into a double digit opinion poll lead as the Tories deal with fall-out from an unpopular Budget and the cash-for-access controversy, a survey showed today.

Two thirds of voters agreed that tax changes announced by Chancellor George Osborne last week show his was "the party of the rich", according to the ComRes research for The Independent.

And the results suggested that questions over the influence of major Conservative donors raised by a weekend expose had sparked a further immediate move away from the party.

The poll puts Labour up three points over the last month on 43%, with the Tories down four at 33% and the Liberal Democrats down two on 11%. Others gained three points to 13%.

About half of the telephone interviews for the survey were carried out on Sunday and Monday, after The Sunday Times revealed the claims of Tory co-treasurer Peter Cruddas.

Among those, Labour enjoyed a 17-point lead.

But in the 337 interviews conducted on Saturday, before the cash-for-access revelations emerged, Labour enjoyed a lead of only four points.

Asked about the Budget, 66% agreed with the statement that "the measures announced...show that the Conservatives are the party of the rich".

A move to freeze personal tax allowances for pensioners was opposed by 59% to 31%.

A second poll, by Populus for The Times, showed a four point lead for Labour over the Tories by 38% (down one) to 34% (down three).

The Liberal Democrats were unchanged on 11% while other parties gained three to 16%.

Almost half (49%) did not believe the pensioner tax allowance move was fair and more (53%) said cutting the top rate of tax from 50p to 45p would do "nothing" to boost the economy.

Only just over a third (35%) believed they would be helped by the increase in the personal tax allowance to £9,205 - 45% said it would make "little or no difference to me".

Voter confidence in the Government's handling of the economy also dipped although Mr Osborne, David Cameron and Nick Clegg still enjoy more confidence than Labour.

They lead Ed Miliband and Ed Balls on that score by 60% to 40% - compared with 66% to 34% last month.

Populus interviewed a random sample of 1,500 adults by telephone and 2,056 adults online between March 23-25.